It is a matter of common knowledge and experience to purchase rolls of vinyl or other plastic wallcoverings and to apply them as decorative surfaces by using modified pressure sensitive adhesives. See, for example, Sackoff, Smith and Walling, U.S. Pat. No. 4,151,319, and copending, Smith, U.S. Pat. application Ser. No. 08/043,388, filed on Apr. 6, 1993, both of which are assigned to the same assignee as the present application. Although embodiments are described in each which state that the laminate can be self wound after peeling the protective release sheet coated with adhesive, in general, these articles require removal of a carrier release liner as part of the application process, because after a few months of storage the rolls cannot be unwound without damaging their decorative surfaces.
It is also known to make cellulose fiber, i.e., paper based, wall coverings, adapted to be affixed to the surface to be decorated with pressure sensitive adhesives. For example, Rothenberg, U.S. Pat. No. 4,555,441, describes a self-adhesive wall covering in which a decorative fabric sheet is glued to an acrylic saturated paper, the wall-facing side of the paper opposite the fabric is coated with a pressure sensitive adhesive, and a release sheet is used to protect the adhesive until just before application to the wall, whereupon the release sheet is removed and discarded. Of special interest is the disclosure in Parkinson, Blakely and Russell, U.S. Pat. No. 3,620,366. Paper based coverings are said to be capable of being self wound and stored for months and yet unwound without damage to the decorative surface of the paper by using a protective coating of a synthetic resin on the decorative surface which acts as a release coat for the adhesive on the back surface. Such a construction obviously avoids the need to remove and discard a release paper during application. However, the exclusive use of cellulose based paper instead of vinyl or other moisture resistant substrates causes unique problems when attempts are made to use self wound rolls of wallcoverings of the type disclosed in the Parkinson et al patent. For example, the coverings are difficult to remove from the surface to be decorated (the "bonding substrate"), especially during the time shortly after application when repositioning is desirable; the normal hygro-expansivity-water is absorbed differentially into the cellulosic fibers resulting in corrugation and lifting from the bonding substrate; application difficulties are experienced, such as poor control of the adhesive properties, often resulting in premature bonding to the substrate or at times no adhesion at all; there is shrinkage, which in not experienced with plastic substrates. All of these drawbacks drive up the amount of waste produced and the cost.
These factors have forced manufacturers of paper wallcoverings to offer prepasted or `apply your own paste` products. Such adhesives, however are generally water reactive cellulosic powders, starch, clay or polyvinyl acetate/polyvinyl alcohol blends which require major handling difficulties in term of application and removing of the product wallpaper from the bonding substrate. Typically these remoistenable adhesives are applied to a ground wood paper for economy, or to a more expensive latex saturated paper for improved durability and removeability. The other side is decorated with a print design and, perhaps, a ground coating to assist durability, print quality and washability of the product.
If, instead of remoistenable adhesives, attempts are made to substitute pressure sensitive adhesives in such constructions, the products fail because the pressure sensitive adhesives, without extreme modification, do not have adequate cohesive strength to resist the expansion and contraction of cellulosic fibers in the paper substrate which naturally inhale moisture from the surrounding atmosphere. Furthermore, the prior art's use of a barrier layer on one side (e.g., Parkinson et al), still does not solve this problem because the product does not possess the necessary repositionability and removability from the bonding substrate.